The principal objective of this project is to develop at the molecular level a mechanistic understanding of the cytochrome P 450 based mixed-function oxygenases. This research will exploit our recent synthesis of a stable ferrous-dioxygen complex which has a hydrophobic pocket on one side of a porphyrin ring. Elaboration of and complexation of hydrocarbon substrates in this hydrophobic pocket; variation of axial bases from imidazoles through sulfur derivatives; and one electron reductions of the hydrocarbon-dioxygen complex with ferrodoxin models are planned. Kinetic studies, determination of magnetic moments, nmr (H and 13C), and Mossbauer spectra are the principal physical chemical methods that will be employed.